The older versions of gcc had a complex.h file in the /usr/include/g++ directory which has been renamed to complex - note the missing .h extension.

There is no complex.h anywhere else on my system. I'm surprised to see it missing if it is indeed part of C99. complex.h is marked broken for gcc-3.3 and hence this may be the reason why it isn't included in NetBSD.

Can you email me the complex.h header and the glibc library that you're currently using? Alternatively, if there is such a thing as a RPM, the RPM will be fine too.

Ok, its working now after applying a lot of hackery. I've isolated the missing complex number routines used by linsmith and copied them into the src directory, modified the corresponding Makefile.am and rebuild the Makefile.in in order to create a Makefile with these new files. I had to modify these files to suit, but this wasn't much of a problem.
Linsmith built cleanly and installed without any further problems. I've tested linsmith following the online tutorial and obtained the same result.

There is just one more thing I've yet to figure out. Linsmith shows the G1 circle but fails to display the actual smith chart, smith4.png, that resides in /usr/local/share/pixmap/linsmith. Any suggestions on this one? However it looks very promising.

the smithchart finally showed-up after using anyone of the zoom functions. It appears to be, that the view isn't repainted after displaying the intro image. Not sure why, but its getting late now, 2:45am, and this will have to wait until later today to be investigated.